<!DOCTYPE html>
<html>
    <head>
        <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
        <!-- 因为 AJAX 库和通用工具的生态已经相当丰富，Vue 核心代码没有重复 -->
<!-- 提供这些功能以保持精简。这也可以让你自由选择自己更熟悉的工具。 -->
<script src="https://cdn.jsdelivr.net/npm/axios@0.12.0/dist/axios.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/lodash@4.13.1/lodash.min.js"></script>
    </head>
    <body>

        <div id="watch-example">
            <p>
              Ask a yes/no question:
              <input v-model="question">
            </p>
            <p>{{ answer }}</p>
          </div>



          <script>

            var excample = new Vue({
                el:"#watch-example",
                data:{
                    question:'',
                    answer:"i cannot give you any anser unitil you give mi the a warite question"
                },
                watch:{
                    // 如果 `question` 发生改变，这个函数就会运行
                    question:function(newQuestion,oldQuestion){
                        this.answer = "wait for you to  stop typing...."
                        this.debounceGetAnswer()
                    }
                },
                created:function(){
                    // `_.debounce` 是一个通过 Lodash 限制操作频率的函数。
                    // 在这个例子中，我们希望限制访问 yesno.wtf/api 的频率
                    // AJAX 请求直到用户输入完毕才会发出。想要了解更多关于
                    // `_.debounce` 函数 (及其近亲 `_.throttle`) 的知识，
                    // 请参考：https://lodash.com/docs#debounce
                    this.debounceGetAnswer = _.debounce(this.getAnswer,500)
                },
                methods: {
                    getAnswer: function () {
                    if (this.question.indexOf('?') === -1) {
                        this.answer = 'Questions usually contain a question mark. ;-)'
                        return
                    }
                    this.answer = 'Thinking...'
                    var vm = this
                    axios.get('https://yesno.wtf/api')
                        .then(function (response) {
                        vm.answer = _.capitalize(response.data.answer)
                        })
                        .catch(function (error) {
                        vm.answer = 'Error! Could not reach the API. ' + error
                        })
                    }
                }
            })

          </script>
    </body>
</html>